As portable electronic devices become more compact, and the number of functions performed by a given device increase, it has become a significant challenge to design a user interface that allows users to easily interact with a multifunction device. This challenge is particular significant for handheld portable devices, which have much smaller screens than desktop or laptop computers. This situation is unfortunate because the user interface is the gateway through which users receive not only content but also responses to user actions or behaviors, including user attempts to access a device's features, tools, and functions. Some portable communication devices (e.g., mobile telephones, sometimes called mobile phones, cell phones, cellular telephones, and the like) have resorted to adding more pushbuttons, increasing the density of push buttons, overloading the functions of pushbuttons, or using complex menu systems to allow a user to access, store and manipulate data. These conventional user interfaces often result in complicated key sequences and menu hierarchies that must be memorized by the user.
Many conventional user interfaces, such as those that include physical pushbuttons, are also inflexible. This may prevent a user interface from being configured and/or adapted by either an application running on the portable device or by users. When coupled with the time consuming requirement to memorize multiple key sequences and menu hierarchies, and the difficulty in activating a desired pushbutton, such inflexibility is frustrating to most users.
To improve usability, some portable devices use a touch screen to render virtual push buttons such as soft keyboards and dial pads. From a user's finger contact with the virtual push buttons, a portable device determines the service(s) requested by the user and takes actions accordingly. But because different users often have different shapes of fingerprints, it has been a challenge for these portable devices to accurately and adaptively identify a user-desired virtual push button based on the different shapes of fingerprints and different contexts associated with different services supported by a portable device.
Accordingly, there is a need for portable multifunction devices that are configured to adaptively determine a cursor position from a finger contact with a touch screen and then perform operations according to the cursor position. Such configuration increases the effectiveness, efficiency and user satisfaction with portable multifunction devices.